What should I say to my parents? They tease me😷

Okay I know that this might gross people out an it grosses me out and I don't want to be judged by it. I'm 13 and was recently having itches in my anus, this is when I then found pinworms in my underwear. I did research and it isn't fatal or deadly but it is uncomfortable and I really want to tell my mum but I think she will tease me. (She always makes fun of things) I just really need help as to how I can tell her. 
It would mean a lot to get help from anybody who has suffered from this. 😷😊